1. Field of the Invention
The present invention relates to a stimuli-responsive composition which contains a polymer, a solvent and a substance having a predetermined function, and which is usable for various functional materials. In particular, the present invention relates to an image-forming material of good dispersion stability, which comprises an aqueous dispersion of the composition and which is favorable for printers and displays, and to an image-forming method and an image-forming apparatus using it.
2. Description of the Related Art
Aqueous dispersions containing solid particles have heretofore been known for functional materials, typically including, for example, agricultural chemicals such as herbicides and insecticides, medicines such as carcinostatic agents, antiallergic agents and anti-inflammatory agents, and coloring materials such as inks that contain colorants such as solid particles and toner. The recent development in digital printing technology is remarkable. Typical examples of digital printing technology are a technology of electrophotography and inkjet recording, and recently, their status in office-use and household-use image-forming techniques is greatly increasing.
In particular, the technology of ink jet recording, as a direct recording method, has the characteristics of being compact and power-saving. Also, in inkjet recording technology, image quality is greatly enhanced by reduction of the size of the nozzle orifices. One example of such an inkjet recording technology includes a method in which ink supplied from an ink tank to a nozzle is heated by a heater on the nozzle to be vaporized and bubbled, and ink is thus ejected from the nozzle to form an image on a recording medium. Another example includes a method in which ink is ejected from a nozzle by vibrating a piezoelectric device. In these methods, an aqueous solution of dye is usually used. In this case, when a plurality of inks are applied, they may blur, and a phenomenon called feathering may occur along the direction of the fibers that constitute the paper at a recording point of a recording medium. To mitigate the phenomenon, use of pigmented ink has been investigated (for example, in U.S. Pat. No. 5,085,698). However, improvement in many points is desired.
The present invention is to provide a stimuli-responsive composition which contains a polymer, a solvent and a substance having a predetermined function. In particular, the present invention is to provide a pigment dispersion ink material in the composition in which the solvent is water and the substance having a predetermined function is a pigment, and which has the advantages of good dispersion stability, an improved blurring resistance and a feathering resistance, and an improved fixability.